The C100L450FM is a Schneider Electric ComPacT NS new generation 4-pole circuit breaker with a MicroLogic 5.0 electronic trip unit, rated 1000 A at 50 °C. For a 1000 A frame, that's a high-interrupt rating; it handles stiff utility feeds or transformer secondaries where fault current runs hot.
The MicroLogic 5.0 gives you LSI protection: long-time overload (L), short-time short-circuit (S) with adjustable pickup and delay, and instantaneous (I). That delay on S lets you coordinate downstream breakers — useful in a distribution panel feeding motor starters or sub-feeders. No ground-fault module here (earth-leakage protection is marked 'without'), so if you need GF, plan for an external relay or a different trip unit. Thermal memory holds for 20 minutes after a trip — the breaker remembers the heating curve so it doesn't immediately reclose into a still-hot load. That matters on motor or transformer circuits where repeated reclosing can cook the winding. The 4 LEDs (red for fault) and one yellow (overload) give you local indication without opening the door. Mechanical durability is 10,000 cycles; electrical durability ranges from 2,000 cycles at full rated current and 690 V up to 4,000 cycles at half current and 440 V. That's typical for a fixed-mount distribution breaker — not a switching device, but it'll handle routine maintenance and fault clearing without wearing out early. Power losses sit at 34 W continuous at rated current — that's heat you need to vent in the enclosure. With IP40 and IK07 mechanical impact protection, it's suited for indoor panel environments where you don't expect water spray or heavy abuse. Backplate mounting, 280 mm wide, 327 mm tall, 147 mm deep — measure your enclosure depth before committing.